From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- arch/sparc/mm/fault_64.c | 544 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 544 insertions(+) create mode 100644 arch/sparc/mm/fault_64.c (limited to 'arch/sparc/mm/fault_64.c') diff --git a/arch/sparc/mm/fault_64.c b/arch/sparc/mm/fault_64.c new file mode 100644 index 000000000..479823249 --- /dev/null +++ b/arch/sparc/mm/fault_64.c @@ -0,0 +1,544 @@ +/* + * arch/sparc64/mm/fault.c: Page fault handlers for the 64-bit Sparc. + * + * Copyright (C) 1996, 2008 David S. Miller (davem@davemloft.net) + * Copyright (C) 1997, 1999 Jakub Jelinek (jj@ultra.linux.cz) + */ + +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +int show_unhandled_signals = 1; + +static inline __kprobes int notify_page_fault(struct pt_regs *regs) +{ + int ret = 0; + + /* kprobe_running() needs smp_processor_id() */ + if (kprobes_built_in() && !user_mode(regs)) { + preempt_disable(); + if (kprobe_running() && kprobe_fault_handler(regs, 0)) + ret = 1; + preempt_enable(); + } + return ret; +} + +static void __kprobes unhandled_fault(unsigned long address, + struct task_struct *tsk, + struct pt_regs *regs) +{ + if ((unsigned long) address < PAGE_SIZE) { + printk(KERN_ALERT "Unable to handle kernel NULL " + "pointer dereference\n"); + } else { + printk(KERN_ALERT "Unable to handle kernel paging request " + "at virtual address %016lx\n", (unsigned long)address); + } + printk(KERN_ALERT "tsk->{mm,active_mm}->context = %016lx\n", + (tsk->mm ? + CTX_HWBITS(tsk->mm->context) : + CTX_HWBITS(tsk->active_mm->context))); + printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %016lx\n", + (tsk->mm ? (unsigned long) tsk->mm->pgd : + (unsigned long) tsk->active_mm->pgd)); + die_if_kernel("Oops", regs); +} + +static void __kprobes bad_kernel_pc(struct pt_regs *regs, unsigned long vaddr) +{ + printk(KERN_CRIT "OOPS: Bogus kernel PC [%016lx] in fault handler\n", + regs->tpc); + printk(KERN_CRIT "OOPS: RPC [%016lx]\n", regs->u_regs[15]); + printk("OOPS: RPC <%pS>\n", (void *) regs->u_regs[15]); + printk(KERN_CRIT "OOPS: Fault was to vaddr[%lx]\n", vaddr); + dump_stack(); + unhandled_fault(regs->tpc, current, regs); +} + +/* + * We now make sure that mmap_sem is held in all paths that call + * this. Additionally, to prevent kswapd from ripping ptes from + * under us, raise interrupts around the time that we look at the + * pte, kswapd will have to wait to get his smp ipi response from + * us. vmtruncate likewise. This saves us having to get pte lock. + */ +static unsigned int get_user_insn(unsigned long tpc) +{ + pgd_t *pgdp = pgd_offset(current->mm, tpc); + pud_t *pudp; + pmd_t *pmdp; + pte_t *ptep, pte; + unsigned long pa; + u32 insn = 0; + + if (pgd_none(*pgdp) || unlikely(pgd_bad(*pgdp))) + goto out; + pudp = pud_offset(pgdp, tpc); + if (pud_none(*pudp) || unlikely(pud_bad(*pudp))) + goto out; + + /* This disables preemption for us as well. */ + local_irq_disable(); + + pmdp = pmd_offset(pudp, tpc); + if (pmd_none(*pmdp) || unlikely(pmd_bad(*pmdp))) + goto out_irq_enable; + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + if (pmd_trans_huge(*pmdp)) { + if (pmd_trans_splitting(*pmdp)) + goto out_irq_enable; + + pa = pmd_pfn(*pmdp) << PAGE_SHIFT; + pa += tpc & ~HPAGE_MASK; + + /* Use phys bypass so we don't pollute dtlb/dcache. */ + __asm__ __volatile__("lduwa [%1] %2, %0" + : "=r" (insn) + : "r" (pa), "i" (ASI_PHYS_USE_EC)); + } else +#endif + { + ptep = pte_offset_map(pmdp, tpc); + pte = *ptep; + if (pte_present(pte)) { + pa = (pte_pfn(pte) << PAGE_SHIFT); + pa += (tpc & ~PAGE_MASK); + + /* Use phys bypass so we don't pollute dtlb/dcache. */ + __asm__ __volatile__("lduwa [%1] %2, %0" + : "=r" (insn) + : "r" (pa), "i" (ASI_PHYS_USE_EC)); + } + pte_unmap(ptep); + } +out_irq_enable: + local_irq_enable(); +out: + return insn; +} + +static inline void +show_signal_msg(struct pt_regs *regs, int sig, int code, + unsigned long address, struct task_struct *tsk) +{ + if (!unhandled_signal(tsk, sig)) + return; + + if (!printk_ratelimit()) + return; + + printk("%s%s[%d]: segfault at %lx ip %p (rpc %p) sp %p error %x", + task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG, + tsk->comm, task_pid_nr(tsk), address, + (void *)regs->tpc, (void *)regs->u_regs[UREG_I7], + (void *)regs->u_regs[UREG_FP], code); + + print_vma_addr(KERN_CONT " in ", regs->tpc); + + printk(KERN_CONT "\n"); +} + +static void do_fault_siginfo(int code, int sig, struct pt_regs *regs, + unsigned long fault_addr, unsigned int insn, + int fault_code) +{ + unsigned long addr; + siginfo_t info; + + info.si_code = code; + info.si_signo = sig; + info.si_errno = 0; + if (fault_code & FAULT_CODE_ITLB) { + addr = regs->tpc; + } else { + /* If we were able to probe the faulting instruction, use it + * to compute a precise fault address. Otherwise use the fault + * time provided address which may only have page granularity. + */ + if (insn) + addr = compute_effective_address(regs, insn, 0); + else + addr = fault_addr; + } + info.si_addr = (void __user *) addr; + info.si_trapno = 0; + + if (unlikely(show_unhandled_signals)) + show_signal_msg(regs, sig, code, addr, current); + + force_sig_info(sig, &info, current); +} + +static unsigned int get_fault_insn(struct pt_regs *regs, unsigned int insn) +{ + if (!insn) { + if (!regs->tpc || (regs->tpc & 0x3)) + return 0; + if (regs->tstate & TSTATE_PRIV) { + insn = *(unsigned int *) regs->tpc; + } else { + insn = get_user_insn(regs->tpc); + } + } + return insn; +} + +static void __kprobes do_kernel_fault(struct pt_regs *regs, int si_code, + int fault_code, unsigned int insn, + unsigned long address) +{ + unsigned char asi = ASI_P; + + if ((!insn) && (regs->tstate & TSTATE_PRIV)) + goto cannot_handle; + + /* If user insn could be read (thus insn is zero), that + * is fine. We will just gun down the process with a signal + * in that case. + */ + + if (!(fault_code & (FAULT_CODE_WRITE|FAULT_CODE_ITLB)) && + (insn & 0xc0800000) == 0xc0800000) { + if (insn & 0x2000) + asi = (regs->tstate >> 24); + else + asi = (insn >> 5); + if ((asi & 0xf2) == 0x82) { + if (insn & 0x1000000) { + handle_ldf_stq(insn, regs); + } else { + /* This was a non-faulting load. Just clear the + * destination register(s) and continue with the next + * instruction. -jj + */ + handle_ld_nf(insn, regs); + } + return; + } + } + + /* Is this in ex_table? */ + if (regs->tstate & TSTATE_PRIV) { + const struct exception_table_entry *entry; + + entry = search_exception_tables(regs->tpc); + if (entry) { + regs->tpc = entry->fixup; + regs->tnpc = regs->tpc + 4; + return; + } + } else { + /* The si_code was set to make clear whether + * this was a SEGV_MAPERR or SEGV_ACCERR fault. + */ + do_fault_siginfo(si_code, SIGSEGV, regs, address, insn, fault_code); + return; + } + +cannot_handle: + unhandled_fault (address, current, regs); +} + +static void noinline __kprobes bogus_32bit_fault_tpc(struct pt_regs *regs) +{ + static int times; + + if (times++ < 10) + printk(KERN_ERR "FAULT[%s:%d]: 32-bit process reports " + "64-bit TPC [%lx]\n", + current->comm, current->pid, + regs->tpc); + show_regs(regs); +} + +asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs) +{ + enum ctx_state prev_state = exception_enter(); + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + unsigned int insn = 0; + int si_code, fault_code, fault; + unsigned long address, mm_rss; + unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE; + + fault_code = get_thread_fault_code(); + + if (notify_page_fault(regs)) + goto exit_exception; + + si_code = SEGV_MAPERR; + address = current_thread_info()->fault_address; + + if ((fault_code & FAULT_CODE_ITLB) && + (fault_code & FAULT_CODE_DTLB)) + BUG(); + + if (test_thread_flag(TIF_32BIT)) { + if (!(regs->tstate & TSTATE_PRIV)) { + if (unlikely((regs->tpc >> 32) != 0)) { + bogus_32bit_fault_tpc(regs); + goto intr_or_no_mm; + } + } + if (unlikely((address >> 32) != 0)) + goto intr_or_no_mm; + } + + if (regs->tstate & TSTATE_PRIV) { + unsigned long tpc = regs->tpc; + + /* Sanity check the PC. */ + if ((tpc >= KERNBASE && tpc < (unsigned long) __init_end) || + (tpc >= MODULES_VADDR && tpc < MODULES_END)) { + /* Valid, no problems... */ + } else { + bad_kernel_pc(regs, address); + goto exit_exception; + } + } else + flags |= FAULT_FLAG_USER; + + /* + * If we're in an interrupt or have no user + * context, we must not take the fault.. + */ + if (in_atomic() || !mm) + goto intr_or_no_mm; + + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); + + if (!down_read_trylock(&mm->mmap_sem)) { + if ((regs->tstate & TSTATE_PRIV) && + !search_exception_tables(regs->tpc)) { + insn = get_fault_insn(regs, insn); + goto handle_kernel_fault; + } + +retry: + down_read(&mm->mmap_sem); + } + + if (fault_code & FAULT_CODE_BAD_RA) + goto do_sigbus; + + vma = find_vma(mm, address); + if (!vma) + goto bad_area; + + /* Pure DTLB misses do not tell us whether the fault causing + * load/store/atomic was a write or not, it only says that there + * was no match. So in such a case we (carefully) read the + * instruction to try and figure this out. It's an optimization + * so it's ok if we can't do this. + * + * Special hack, window spill/fill knows the exact fault type. + */ + if (((fault_code & + (FAULT_CODE_DTLB | FAULT_CODE_WRITE | FAULT_CODE_WINFIXUP)) == FAULT_CODE_DTLB) && + (vma->vm_flags & VM_WRITE) != 0) { + insn = get_fault_insn(regs, 0); + if (!insn) + goto continue_fault; + /* All loads, stores and atomics have bits 30 and 31 both set + * in the instruction. Bit 21 is set in all stores, but we + * have to avoid prefetches which also have bit 21 set. + */ + if ((insn & 0xc0200000) == 0xc0200000 && + (insn & 0x01780000) != 0x01680000) { + /* Don't bother updating thread struct value, + * because update_mmu_cache only cares which tlb + * the access came from. + */ + fault_code |= FAULT_CODE_WRITE; + } + } +continue_fault: + + if (vma->vm_start <= address) + goto good_area; + if (!(vma->vm_flags & VM_GROWSDOWN)) + goto bad_area; + if (!(fault_code & FAULT_CODE_WRITE)) { + /* Non-faulting loads shouldn't expand stack. */ + insn = get_fault_insn(regs, insn); + if ((insn & 0xc0800000) == 0xc0800000) { + unsigned char asi; + + if (insn & 0x2000) + asi = (regs->tstate >> 24); + else + asi = (insn >> 5); + if ((asi & 0xf2) == 0x82) + goto bad_area; + } + } + if (expand_stack(vma, address)) + goto bad_area; + /* + * Ok, we have a good vm_area for this memory access, so + * we can handle it.. + */ +good_area: + si_code = SEGV_ACCERR; + + /* If we took a ITLB miss on a non-executable page, catch + * that here. + */ + if ((fault_code & FAULT_CODE_ITLB) && !(vma->vm_flags & VM_EXEC)) { + BUG_ON(address != regs->tpc); + BUG_ON(regs->tstate & TSTATE_PRIV); + goto bad_area; + } + + if (fault_code & FAULT_CODE_WRITE) { + if (!(vma->vm_flags & VM_WRITE)) + goto bad_area; + + /* Spitfire has an icache which does not snoop + * processor stores. Later processors do... + */ + if (tlb_type == spitfire && + (vma->vm_flags & VM_EXEC) != 0 && + vma->vm_file != NULL) + set_thread_fault_code(fault_code | + FAULT_CODE_BLKCOMMIT); + + flags |= FAULT_FLAG_WRITE; + } else { + /* Allow reads even for write-only mappings */ + if (!(vma->vm_flags & (VM_READ | VM_EXEC))) + goto bad_area; + } + + fault = handle_mm_fault(mm, vma, address, flags); + + if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + goto exit_exception; + + if (unlikely(fault & VM_FAULT_ERROR)) { + if (fault & VM_FAULT_OOM) + goto out_of_memory; + else if (fault & VM_FAULT_SIGSEGV) + goto bad_area; + else if (fault & VM_FAULT_SIGBUS) + goto do_sigbus; + BUG(); + } + + if (flags & FAULT_FLAG_ALLOW_RETRY) { + if (fault & VM_FAULT_MAJOR) { + current->maj_flt++; + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, + 1, regs, address); + } else { + current->min_flt++; + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, + 1, regs, address); + } + if (fault & VM_FAULT_RETRY) { + flags &= ~FAULT_FLAG_ALLOW_RETRY; + flags |= FAULT_FLAG_TRIED; + + /* No need to up_read(&mm->mmap_sem) as we would + * have already released it in __lock_page_or_retry + * in mm/filemap.c. + */ + + goto retry; + } + } + up_read(&mm->mmap_sem); + + mm_rss = get_mm_rss(mm); +#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE) + mm_rss -= (mm->context.huge_pte_count * (HPAGE_SIZE / PAGE_SIZE)); +#endif + if (unlikely(mm_rss > + mm->context.tsb_block[MM_TSB_BASE].tsb_rss_limit)) + tsb_grow(mm, MM_TSB_BASE, mm_rss); +#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE) + mm_rss = mm->context.huge_pte_count; + if (unlikely(mm_rss > + mm->context.tsb_block[MM_TSB_HUGE].tsb_rss_limit)) { + if (mm->context.tsb_block[MM_TSB_HUGE].tsb) + tsb_grow(mm, MM_TSB_HUGE, mm_rss); + else + hugetlb_setup(regs); + + } +#endif +exit_exception: + exception_exit(prev_state); + return; + + /* + * Something tried to access memory that isn't in our memory map.. + * Fix it, but check if it's kernel or user first.. + */ +bad_area: + insn = get_fault_insn(regs, insn); + up_read(&mm->mmap_sem); + +handle_kernel_fault: + do_kernel_fault(regs, si_code, fault_code, insn, address); + goto exit_exception; + +/* + * We ran out of memory, or some other thing happened to us that made + * us unable to handle the page fault gracefully. + */ +out_of_memory: + insn = get_fault_insn(regs, insn); + up_read(&mm->mmap_sem); + if (!(regs->tstate & TSTATE_PRIV)) { + pagefault_out_of_memory(); + goto exit_exception; + } + goto handle_kernel_fault; + +intr_or_no_mm: + insn = get_fault_insn(regs, 0); + goto handle_kernel_fault; + +do_sigbus: + insn = get_fault_insn(regs, insn); + up_read(&mm->mmap_sem); + + /* + * Send a sigbus, regardless of whether we were in kernel + * or user mode. + */ + do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, address, insn, fault_code); + + /* Kernel mode? Handle exceptions or die */ + if (regs->tstate & TSTATE_PRIV) + goto handle_kernel_fault; +} -- cgit v1.2.3-54-g00ecf